The great experiment is over. The technology which would, we were promised, provide "electricity too cheap to meter" has failed: nuclear power in Britain is melting down. Germany, Sweden and Japan have all banned their imports of mixed oxide fuel from Britain. The Nuclear Installations Inspectorate has reported "systematic management failures" at Sellafield. The government is proposing to abandon nuclear reprocessing in Britain, and if it falters Ireland and Denmark will force its hand in June. The planned privatisation of British Nuclear Fuels (BNFL) has been suspended. Analysts have been puzzling over why the industry should be collapsing so quickly. But the question we should surely be asking is how it has survived so long.

Nuclear power has never been viable. The electricity it produces costs 4p per kilowatt/hour. Gas costs 2p and wind power 3p. Handling nuclear waste and decommissioning the plants has never been fully costed: Britain could be faced with a £30bn shortfall. The nuclear industry has been sustained only by government subsidies and opaque accounting.

Nuclear power is also the world's most dangerous business. If Sellafield's antiquated liquid waste tanks were to blow, they would release as much radiation as 10 Chernobyls. Britain has already accumulated enough nuclear waste to build 5,000 atom bombs. Reprocessing, upon which the industry now relies to justify its existence, increases both the quantity of bomb-grade plutonium and the opportunities for stealing it. The children of women who have worked in nuclear installations, according to a study by the National Radiological Protection Board, are 11 times more likely to contract cancer than the children of workers in non-radioactive industries. You can tell how close to Sellafield children live by the amount of plutonium in their teeth.

Fifty years of secrecy and deceit have compounded these problems. Britain's nuclear power programme began with a lie: it was, in fact, a smokescreen for our nuclear weapons programme. It has been supported by lies ever since. Windscale caught fire in 1957, but the full extent of the disaster was covered up until 1988. As a result, scores of local people contracted cancers which might have been avoided. The government learnt a valuable lesson from the disaster: it changed the installation's name to Sellafield and decided that, thenceforth, it would invest in expensive public relations campaigns. When the waste tip at Dounreay exploded in 1977, the industry heroically halved its response time: the public had to wait for only 18 years before discovering that it had been living with the hazardous results.

The radiation industry has always found ingenious means of securing its survival. In the 80s it persuaded the government to abandon research on wave energy, by fiddling the figures to make it look more expensive than nuclear power. For the past 20 years a BNFL employee has enjoyed diplomatic status in the British embassy in Tokyo: he appears to have filtered out information suggesting that the Japanese market for reprocessed nuclear fuel was less than robust. In 1998, BNFL planned to import thousands of spent nuclear fuel rods from America without notifying either the US or British governments.

It asked US companies to "doctor" their communications with the federal administration. Privatisation offered the industry a means by which it might shed many of its decommissioning costs, leaving them with the taxpayer while it distributed the assets to shareholders. Concealed by "commercial confidentiality", the industry's expenses are routinely downplayed and its benefits routinely exaggerated.

Both Sellafield's Thorp reprocessing plant and its new mixed oxide plant were built before the company had obtained a licence to run them: it calculated that, after spending £2.1bn of taxpayers' money, the government would not reject its schemes. The Tories rigged the public decision-making process in order to allow Thorp to operate, and Labour's Stephen Byers keep it afloat by spreading the falsehood that Germany was contractually obliged to buy the fuel it produced. When governments breed white elephants, the public gets trampled.

Nuclear power, in other words, has been protected in Britain from both public scrutiny and market disciplines. A company manufacturing teddy bears under these circumstances would be a public hazard. Charged with handling the most dangerous substances on earth, the atom business is a terrifying menace.

But the industry is now running out of fabrications, and its long-awaited nemesis seems at last to have arrived. It is time to shut nuclear power down, and begin the dangerous and expensive task of decommissioning Britain's most disastrous experiment.